Uploaded image doesn't match original file

I designed this green with yellow stars graphic to match the hex of the color green on this page https://thecleanwaterexpert.com/reviews

When I upload the image, something in the processing changes the coloration of the file.  Please see the attached screenshot which shows the green color to be matched (the button), next to the color of the file that is uploaded (shows correctly in the edit window) , and the final color output when the image is inserted into the page design that is incorrect.

I have tried adjusting the brightness and saturation of the image but none of them come close to matching the original, correct colors of the file.  Does anyone know how to fix or report this bug?  I know others have had this problem.